Tested nouveau on G5 PPC64, it works fine. I really don't understand why video_cards_nouveau is masked.
Can you also add x11-base/xorg-drivers -video_cards_nouveau and media-libs/mesa -video_cards_nouveau in /usr/portage/profiles/arch/powerpc/package.use.mask ?

Tested nouveau on G5 PPC64, it works fine. I really don't understand why video_cards_nouveau is masked.
Can you also add x11-base/xorg-drivers -video_cards_nouveau and media-libs/mesa -video_cards_nouveau in /usr/portage/profiles/arch/powerpc/package.use.mask ?

Thanks a lot for you help !

When you say 'works fine', what exactly do you mean? I recently tried installing nouveau on a G5, and while I get some display -- I get many artifacts, and it is *very* low quality video. I might be missing something though...